Roll forming machine for producing cellular core panels



July 15, 1969 J. w, ALLEN 3,455,135

ROLL FORMING MACHINE FOR PRODUCING CELLULAR CORE PANELS INVENTOR John M. Allen ATTORNEY July 15, 1969 J. w. ALLEN 3,455,135

ROLL FORMING MACHINE FOR PRODUCING CELLULAR CORE PANELS INVENTOR ATTORNEY John W Allen y 5, 1969 J. w. ALLEN 3,455,135

ROLL FORMING MACHINE FOR PRODUCING CELLULAR CORE PANELS Filed Aug. 15, 1967 4 Sheets-Sheet 5 INVENT OR John M. Allen BY imm ATTORNEY Jul 15, 1969 J. w. ALLEN 3,

ROLL FORMING MACHINE FOR PRODUCING CELLULAR CORE PANELS Filed Aug. 15 1967 4 Sheets-Sheet 4 INVENTOR John W A//en ATTORNEY United States Patent 3,455,135 ROLL FORMING MACHINE FOR PRODUCING CELLULAR CORE PANELS John W. Allen, Flossmoor, Ill., assignor to Stanray Corporation, Chicago, 11]., a corporation of Delaware Filed Aug. 15, 1967, Ser. No. 660,788 Int. Cl. B2lb 1/04, 1/12, 1/18 US. Cl. 72-187 ABSTRACT OF THE DISCLOSURE A metal forming machine having two stages of cooper ating top and bottom mechanically driven rollers between which a metal sheet having a plurality of lines of slits can be moved to form said sheet into an integral cellular core panel. Lines of blades on the periphery of one roller in the first stage progressively mate with lines of punches on the periphery of the other roller of this stage as the rolls rotate. Said lines of blades and punches initially partially fold the sheet in the unslit portions of each slit line at the same time that the punches enter and expand 8 Claims the slits in each line. The second stage includes cooperp} SUMMARY OF THE INVENTION The invention relates to the field of metal forming apparatus and more specifically to a roll forming machine having two stages of cooperating rollers through which a preslit flat metal sheet can be moved to form the sheet into an integral cellular core panel.

While the prior art has taught a number of ways in which cellular core panels of the general nature contemplated by this invention'can be manufactured, such means have not been entirely satisfactory. For example, it is well known that honeycomb-type cores or cellular core panels can be produced by the use of a plurality of corrugated strips of metal which can be bonded together by means of cements, welding and clamping or other metal securing means. Also, it has been previously known that in making metal grates a metal plate can be slit and bent and then vertically twisted to form hexagonal-shaped walls through a suitable rectifying operation. Unfortunately, these previously used techniques for producing the honeycomb-type core structures have not been completely satisfactory from either a quality or a production standpoint. For example, it has been found that cements may deteriorate and the component parts of the core structure can become separated from one another under condi tions of high temperature and high order stresses. Likewise, where a number of structural pieces must be assembled and formed into an integral core through the use of welding or other metal securing techniques, it often happens that such techniques for securing the individual pieces are not uniform in quality and in certain cases this lack of uniformity can result in a breakdown or deterioration of the core structure. Furthermore, production schedules which involve the assembly of a number of component parts that must be then set up and individually secured together by whatever means necessary, or which involve a number of operations, tend to result in slow schedules and higher costs.

One way in which the disadvantages of previously known methods and machines for forming a cellular core panel can be overcome is illustrated in copending application Ser. No. 656,781, filed July 28, 1967. The apparatus disclosed in this copending application involves the use of top and bottom dies in a mechanical vertically operated press and these dies are designed to work on a preslit metal sheet as the sheet is progressively moved through the machine in a series of steps. The apparatus disclosed in this copending application also includes means for gathering the sheet material in the direction of (the slit lines during the operation so as to avoid ruptures and material strains in the final core panel. However, such apparatus does require some method of shifting the dies relative to each other during the operation of the press and this results in an increase of the number of machine components required.

The roll forming machine to be described herein avoids the disadvantages of methods and machines previously known and in addition simplifies to some degree the type of apparatus which is used to form a cellular core panel from a preslit metal sheet.

The preslit metal sheet on which the machine is designed to operate consists of a sheet which is accurately slit in a plurality of equally spaced longitudinally extending lines having unslit portions between adjacent slits in each line. The slit lines are parallel to each other and to the side edges of the sheet.

In the first stage of the machine there are a plurality of alternately disposed lines of blades and punches around the periphery of the top and bottom rolls. These lines on each roller are coaxially disposed relative to the longitudinal center line of the rolls and as the preslit sheet is moved between the rolls, these lines extend across the width of the sheet. In the machine the first stage is set up so that as the rolls rotate, a line of blades on one roll will progressively move in and out of mating engagement with a line of punches on the other roll and in so doing will form that portion of the metal sheet lying between these rolls.

Before describing the operation of the first stage of the machine, it should be pointed out that the position of each of the blades in the blade lines and each of the punches in the punch lines must be accurately positioned so that they can simultaneously operate along the slit lines in the sheet. The blades in each line of a' roll are spaced along the line and are offset from the punches in the adjacent lines of the roll. The lines of the blades and punches on the other roll are positioned so that they mate with their corresponding lines on the other roll dur ing the work operation on the sheet of metal.

Having in mind the relative disposition of the blades and the punches on the two rolls of the first stage, the operation of this stage will now be described. As the operation commences, the preslit sheet is advanced into the first stage so that the unslit portions of alternate slit lines are in a position to be folded by the progressive mating action of a line of blades on one roll acting in conjunction with a line of punches on the other roll as the rolls are rotated. At the same time, of course, the punches will be expanding the slits in the adjacent alternate slit lines. After these mating lines on the top and bottom rolls have disengaged, it should be apparent that the next succeeding line of cooperating blades and punches will then be entering into mating engagement and that the only difference in the forming operation lies in the fact that the folding and expanding of the sheet will be in an opposite direction to that done by the preceding line.

The net result in this first stage operation is the formation of a plurality of contiguous cells in one line extending across the original width of the sheet and joined by bent together connecting Walls opening downward, for example. There will be a similar line of contiguous cells disposed adjacent said one line but joined by bent together connecting Walls opening upward. It will be understood that these connecting walls will be laterally or transversely ofiset with respect to said connecting walls in said one line and will also be medially aligned with the cells in said first line. Repeated operation of the rolls on the sheet as it is stepped through the machine will produce a cellular-type core.

Immediately after the sheet material has passed through the first stage of the machine the partially formed core is passed to a second stage of the machine. The opeartion in this second stage is concerned with more tightly bending the connecting walls between the contiguous cells in each line of cells and with a final forming of each cell. It will be understood that the initial bending as performed in the first stage operation will result in the Walls being bent through a total angle of some 160 so that the connecting walls open either downwardly or upwardly in a slightly opened U configuration. In order to completely close this configuration so that the connecting walls are forced to a tight position normal to the original plane of the sheets, cooperating lines of squeeze members are positioned around the pereiphery of a pair of rolls similar to those used in the first stage. As the rolls in the second stage rotate they receive the partially completed core from the first stage and closely flatten the connecting walls and expand the cells to the desired shape. It will be appreciated, of course, that these two stage operations are continuous so that each operation, except the first and last on each sheet, involves the preliminary formation of cells at the same time that previously formed cells are being squeezed into final shape.

BRIEF DESCRIPTION OF DRAWINGS FIGURE 1 is a side view showing the arrangement of blades and punches on the rolls of the first stage together with the arrangement of the squeeze members on the rolls of the second stage of the machine.

FIGURE 2 is a view taken along line 2-2 of FIG- URE 1.

FIGURE 3 is a view taken along line 33 of FIG- URE 2.

FIGURE 4 is a view taken along line 4-4 of FIG- URE 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT The roll forming machine used for forming a cellular core panel from the preslit metal sheet includes a first stage of rolls, generally indicated at 10, and a second stage of rolls, generally shown at 11. The first stage includes a top roll 12 and a bottom roll 13 while the second stage has top roll 14 and bottom roll 15.

As seen in FIGURES 2 and 3, the rolls 12 and 13 of the first stage are supported on the machine frame 16 by upright bearing supports 17 and 18. The features of the bearings are not shown in detail as they form no part of the invention, but the shaft ends 19, 20, 2'1 and 22 of top rolls 12 and 13, respectively, are shown projecting into the bearing supports 17 and 18, respectively. It will be noted that shaft ends 19 and 21 project through bearing support 17 to be secured to gear drive members 23 and 24. For clarity of disclosure, no details of the gear drive for the rolls is given but it is believed well known in the art and any suitable arrangement can be used.

Referring now to FIGURES 1 and 3, it will be observed that the top roll 12 carries a plurality of alternately spaced lines of punches and blades. For convenience of discussion, the lines of punches on the top roll 12 have been generally indicated at 25 while the lines of blades are generally indicated at 26. Similar punches and blades on the bottom roll 13 have been generally indicated at 27 and 28, respectively. A more complete description of these individual punches and blades will be given later, but for the moment it can be seen that as the top roll 12 is rotated in a counterclockwise direction and bottom roll 13 in a clockwise direction, through the gear drives 23 and 24, respectively, a line of punches on one roll will progressively meet and retract from mating engagement with a line of blades on the other roll in the area adjatient to the common plane of the center lines of the re ls.

Specifically referring to FIGURE 1, it can be seen that at the particularly position shown, a line of blades 26 on top roll 12 is in full mating engagement with a punch line 27 on the bottom roll 13. Assuming the rolls continue to rotate, it will be understood that the following blade line 28 on bottom roll 13 will next mate with its associated punch line 25 on the top roll 12. This sequence of operations will continue as the rolls continue to rotate and as a preslit sheet, generally indicated at 29, is positioned between the rolls 12 and 13 it is belived obvious that a blade line will act against an associated punch line alternately from the top and bottom of said sheet 29.

Before describing the manner in which the lines of punches and blades in the first stage 10 form the sheet 29, it is necessary to more fully describe the punches and blades and also the exact manner in which the sheet 29 is slit. Looking first at FIGURE 3, a blade line 26 on top roll 12 is shown as having three blades, generally indicated at 30, and mounted on the base 31. This base 31 is secured by any desired means, as by keying, not shown, to the periphery of roll 12. It will be noted that each blade 30 has upwardly converging walls 32, 32 terminating in a top surface 33. It will also be observed, as seen in FIGURE 1, that the leading and trailing edges of the individual blades 30 diverge outwardly from base 31 so that the top surface 33 is in the form of an arc of a circle.

The individual blades of the blade lines 28 on the bottom roll 13 are identical to those on the top roll 12 and have been generally labeled 30'. Attention is directed to the fact that there are only two blades 30' in each blade line 28.

Next considering the punch lines 27 on bottom roll 13, it can be seen, partially well on FIGURES 1 and 3, that the punches, generally indicated at 34, consist of a block that has a rectangular base portion 35 which is secured to roll 13. Side edges 36 and 37 slope inwardly towards the center of the punch and there is a notched portion with inwardly converging walls 38 and 39. In FIGURE 1 it can be observed that the leading edge 40 and trailing edge 41 of each punch'34 converge upwardly to a top wall 42.

The punches 34' is the punch lines 25 on top roll 12 are similar to those on the bottom roll 13 except that the side edges are not sloped and that there are two notched portions with inwardly converging walls labeled 38 and 39'.

Attention is directed next to FIGURE 2 of the drawings and the preslit sheet of metal 29. As can be seen in the figure, this sheet includes a number of lines of slits with unslit portions therebetween, and these lines extend longitudinally of the sheet 29. For convenience in the later discussion of the manner in which the sheet is positioned to he stepped through the rolls and the operation of the rolls on the sheet, the side edges of the sheet and slit lines are labeled by the numerals 43, 44, 45, 46 and 47 at the break line of the sheet and as reading from top to bottom.

It will be noted that all of the slit lines are parallel to each other and to the side edges of the sheet. In addition, each slit must be of the same length and the centers of the unslit portions in the slit lines must be at the centers of the slits in the two adjacent slit lines. It is also important to understand that the distance between parallel slit lines must be equal to the desired depth of the cellular core panel, to be formed in the apparatus. A further consideration relates to the relative lengths of the slits and the unslit portions in each line. For example, it has been found that if a sheet is so slit that the slit lengths are three times the unslit portions in each line, then the cells as formed in the apparatus will be of a true hexagonal shape formation. However, other proportions of length can be used as desired.

Considering now the operation of the first stage of the machine, the sheet 29 is positioned so that slits in alternate slit lines 44 and 46 are centered to be opened up and expanded by the action of the punch line 27 on bottom roll 13 moving clockwise at the same time that the blade line 26 is bending the unslit portion of slit line 45 and side edges 43 and 47 in the notched and sloping sides 36 and 37 of the punch line 27. This operation can be seen particularly well in FIGURE 2 where the three blades 30 of blade line 26 are in full mating engagement with the punch 34. As can be observed in this figure, two partially formed cells with an upwardly opening saddle, as generally indicated at 48, have been produced. As the blade and punch lines disengage because of further rotation of the rolls 12 and 13, the sheet 29 is advanced so that the two blades 30' of blade line 28 operate in conjunction with the punch line 34 on top roll 12 to form a single cell with downwardly opening saddles as generally shown at 49. At this point it should be mentioned that suitable means, not shown, are used in conjunction with the roll forming machine to step the sheet 29 forward in a series of steps for operation between the rolls of the first and second stage. While such apparatus is not shown, this technique is well known in the art and any suitable means may be used.

The process described above is repetitious as the rolls continue to rotate and the preslit sheet 29 is stepped into the machine. It should be emphasized at this point that while an arrangement has been shown to operate on a sheet with only three slit lines, the arrangement could be expanded to take care of a much wider sheet having additional slit lines so as to produce a core with more cells extending across the width of the panel.

It has been previously mentioned that in the machine disclosed in copending application Ser. No. 656,781, means have been provided for gathering the sheet material in the direction of the slit lines while the material is being in order to prevent ruptures and material strains in the final core. This problem is simply handled in the presently disclosed roll forming machine by making the diameter of the rolls such that the sheet can contract during the forming operation between the rolls. This, of course, eliminates the need for additional machine components such as those shown in the copending application.

As seen in FIGURE 2, the cellular core produced in the first stage of the roll forming machine is not a finished product. Thus, the saddle portions 48 and 49 have about a 160 bend and the side walls about an 80 bend to the original plane of the sheet 29. In order to complete the formation of the cellular core panel the second stage 11 is designed to complete the desired bending of the saddles and the walls and this stage will now be described. In FIGURES 2 and 4- the machine frame 16 is shown as having upright bearing supports 50 and 51 on which top roll 14 and bottom roll are supported. These rolls are rotated by means of gear drives 52 and 53, and as this structure is exactly like that involved in the first stage of the machine, it is not thought necessary to further describe it.

In FIGURE 1 the top and bottom rolls 14 and 15, respectively, of the second stage of the machine are shown as carrying alternate lines of a first squeeze member and a second squeeze memberin a manner similar to that of the punches and blades of the first stage. For ease of description, the first squeeze members on the top roll 14 have been generally labeled 54 and the lines of the second squeeze members on the roll 14 are generally labeled 55. Corresponding squeeze members on the bottom roll 15 are labeled 54' and 55.

Considering the first squeeze member 54, as seen best in FIGURES 1 and 4, it can be observed that it includes a generally rectangular-shaped base 56 suitably secured to roll 14. Three notches with inwardly converging walls 57 and 58, that terminate in a slot 59, extend across the width of the squeeze member 54. Squeeze member 54' on bottom roll 15 is similar to squeeze member 54 except that it has only two notches with slots 59.

The second squeeze member 55 also has a generally rectangular-shaped base 60 secured to the top roll 14. It will be noted that the second squeeze member 55 does not extend outwardly from the periphery of the roll 14 as far as does the first squeeze member 54. However, in a manner similar to the first squeeze member this second squeeze member 55 has spaced notches on its top surface. In the second squeeze member 55 there are two notches formed by inwardly converging sides 61 and 62 that terminate in a slot 63. The second squeeze member 55 on bottom roll 15 is similar to that of the top with the exception that there are three notches with slots 6-3.

Referring at this time to FIGURES 1, 2 and 4, it can be seen that as the rolls 14 and 15 rotate, first and second squeeze members mate at the area where the two rolls are closest to each other. As the squeeze members do move in and out of mating engagement, they receive the partially completed core being formed at the first stage of the machine. It will be recalled that in this first stage the saddle portions 48 and 49 and the side walls of the individual cells were not completely bent to a position where the cells will be transversely or normally disposed relative to the original plane of the sheet 29. This latter result is accomplished in the second stage where the first squeeze members 54 have relatively wide notches to receive the open side of the folded portions 48 and 49 of the partially completed core. It can also be seen that the natches in the second squeeze members 55 are narrower because the folded edges of the saddle portions 48 enter these notches. Thus, as the first and second squeeze members come together, the diverging walls of the folded portions, such as at 48 and 49, are urged together in the first squeeze member 54 simultaneously with a crimping action at the closed end of the fold or saddle that takes place in the second squeeze member 55. Such action is shown in dashed lines'in FIGURE 4 and the finally completed core with the hexagonally-shaped cells transversely disposed in relation to the original plane of the sheet 29, as it enters the first stage 10', is shown at the right side of FIGURE 2 From the foregoing it is evident that I have devised an improved apparatus for transforming a flat sheet of metal into an integral cellular core member, and the above description of the invention taken with the accompanying drawings is believed to be amply suificient for one skilled in this art to make and perform the invention.

Iclaim:

1. A roll forming machine for forming a cellular panel from a flat sheet of material having a series of parallel slit lines equally spaced from each other, and the side edges of the sheet, including a pair of rolls, a plurality of alternate lines of punches and blades, projecting from the periphery of each roll, means for simultaneously rotating said rolls, so that lines of'punches on one roll successively move into and out of mating engagement with lines of blades on the other roll, means for positioning a portion of said sheet between said rolls so that the slit lines of said sheet will register with the lines of punches and blades on said rolls, whereby as an associated pair of lines mate, the blades will partially fold the sheet material upon itself at the unslit part of the slit lines of said sheet, while the punches partially expand the sheet material adjacent the slits in the slit lines, said blades and punches on said rolls sequentially advancing a next portion of said sheet to a position to be worked on by the next succeeding pair of associated blades and punches on said rolls, whereby said sheet can be stepped through the machine in a plurality of forming operations.

2. The machine as in claim 1 wherein as the blades and punches mate and deform the material, the material is slightly gathered in the direction of the slit lines, so that the width of the finish panel is the same as the original Width of the slit flat sheet.

3. A roll forming machine for forming a cellular panel from a flat metal sheet having a series of parallel slit lines equally spaced from each other and the side edges of the sheet, including a forming stage with a pair of rolls, a plurality of alternating lines of punches and blades on each roll, power means for simultaneously rotating said rolls so that lines of punches on one roll move into and out of mating engagement with lines of blades on the other roll in the area adjacent the common plane of the longitudinal center lines of said rolls, means to move a portion of said sheet to a position between said rolls so that as an associated pair of lines mate the blade lines will partially fold the sheet material upon itself at the unslit part of the slit lines while the punches also partially expand the sheet material adjacent the slits in the slit lines, said punches and blades simultaneously sequentially advancing a next portion of said sheet to a position to be worked on by the next succeeding pair of associated lines on said rolls whereby the sheet can be stepped through the machine in a plurality of forming operations.

4. The machine as in claim 3 wherein said panel is further formed in an additional forming stage, said additional forming stage having a pair of rolls with power drive means for simultaneously rotating said rolls, each of said rolls in said additional stage having a plurality of alternately and peripherally disposed first and second squeeze members positioned to meet in mating engagement about a portion of said panel as advanced from said forming stage to further bend and expand the sheet material to a position wherein the cells of the panel are transversely disposed relative to the original plane of the sheet.

5. The machine as in claim 4 wherein said first squeeze members crimp the closed end of the bent portions of the sheet in cooperation with said second squeeze members which simultaneously force the open ends of the bent portions together whereby the two wall portions between adjacent contiguous cells lie parallel to each other and transversely disposed relative to the original plane of the fiat sheet.

6. Apparatus for forming a cellular panel from a metal sheet having a series of parallel slit lines equally spaced from each other and the side edges of the sheet, including a roll forming machine with two stages of power driven cooperating top and bottom rolls, a first stage having a plurality of alternately disposed lines of blades and punches peripherally disposed on said rolls and extending across the width of said sheet as received therebetween, means advancing a portion of said sheet to a position between a mating line of blades on one roll and a line of punches on the other roll, said blade line partially folding the sheet material on itself at the unslit sections of the slit lines While the punches are partially expanding the material adjacent the slit portions of said slit lines, said sheet advancing means sequentially moving the following and remaining portions of said sheet to said position between said rolls and the partially formed sections of said sheet to a second stage, said second stage having a plurality of alternately arranged first and second squeeze members peripherally disposed on the surface of each roll and positioned to receive a partially formed section of said sheet therebetween, a mating action between a first squeeze member on one roll and an associated second squeeze member on the other roll further bending and expanding the partially formed section of said sheet so that the cells of the finally formed panel are transversely disposed relative to the original plane of the flat sheet and the outer surfaces of the bent portions of the panel lie in planes parallel to the original plane of said sheet.

7. Apparatus for forming a cellular core panel from a metal sheet having a series of parallel slit lines equally spaced from each other and the side edges of the sheet, including a roll forming machine having spaced first and second stages of associated rolls through which said sheet can be moved in a sequence of operations, said first stage having top and bottom rolls adapted to be simultaneously rotated, a plurality of alternating lines of punches and blades peripherally disposed upon each roll and extending across the width of said sheet as received between the lines on the rolls, the lines being so disposed on the respective rolls that a blade line and an associated punch line progressively meet and retract in mating engagement on the sheet in the area of the common plane between the longitudinal center lines of the two rolls, means positioning a portion of said sheet in said area so that said blade lines partially bend the sheet on itself at the unslit portions of alternate slit lines while the punches simultaneously partially expand the sheet material adjacent the slit sections of the remaining alternate slit lines, said blades and punches advancing said sheet during each period between the retraction of a pair of mating lines and the meeting of the next succeeding pair of mating lines, said second stage having a top and a bottom roll simultaneously driven by power means and adapted to receive the sheet as partially formed in said first stage, said rolls of said second stage each having a plurality of alternately peripherally disposed first and second squeeze members, the first squeeze member on one roll being moved into and out of mating engagement with a second squeeze member on the other roll as the rolls rotate, said sheet positioning means moving a section of said partially formed sheet to a position whereby said first squeeze member crimps the closed end of each of the bends in that section while the second squeeze member urges the partially opened ends of said bends together to form a plurality of integrally joined contiguous cells transversely disposed in relation to the plane of the sheet as received in the first stage of the machine.

8. The apparatus of claim 7 wherein the spacing of said first and second stages of associated rolls is such as to allow for proper contraction of the sheet as it is partially and fully expanded while moving through the rolls.

References Cited UNITED STATES PATENTS 1,602,049 10/1926 Somers 72-196 1,938,318 12/1933 Colby 72-196 3,162,942 12/1964 Christman 72-185 CHARLES W. LANHAM, Primary Examiner LOWELL A. LARSON, Assistant Examiner U.S. Cl. X.R. iii; 51

UNITED STATES PATENT ()FFICE CERTIFICATE OF CORRECTION Patent No. 3,455,135 July 15 1969 John W. Allen It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Column 3, line 10, "opeartion" should read operation line 22, "pereiphery" should read periphery Column 4 line 8, "particularly should read particular line 40, "partially" should read particularly line 49, "is" should read in Column 5 line 42, after "being I insert bent Column 6, line 21 after "top" insert roll line 38 "matches should read notches Signed and sealed this 14th day of April 1970.

(SEAL) Edward M. Fletcher, Jr.

Commissioner of Patents Attesting Officer 

